Diabetes is a degenerative disease, which is caused by abnormal levels of glucose in the cell. These abnormal levels of glucose are not easily predictable and or measurable. Currently, home use technologies to determine different levels of glucose are not very accurate or are not able to determine lower levels (below 20 mg/dl). Additionally, the abnormal levels of glucose have been correlated with the production of insulin. Type 1 diabetes is where the body is unable to produce insulin. Type 2 diabetes is when insulin is produced but the body destroys the insulin or is unable to recognize it.
Currently, the most used technologies to determine glucose levels involve enzyme reaction methods. These methods determine glucose in whole blood, plasma or serum. The methods include glucose oxidase, hexoquinase, and glucose dehydrogenase enzyme methods. The products of these reactions between the enzyme and blood sugar can be determined with colorimetric and spectrophotometric assays. Alternatively, they can be measured by the electric current produced in the reaction, which is the case for most commercially-available glucose meters. These methods are accurate and are becoming more sensitive, detecting glucose concentrations from 0 to 500 mg/dl for laboratory assays and 20 to 500 mg/dl for home monitoring. However, these methods can give falsely high values of glucose with different environmental or medical treatments. These methods can also provide uncertain values such as the incompatibility of the meters and the strips, which is one of the persistent problems of the methods.
The cost of current methods for measuring blood sugar levels is also an impediment, which ranges from about $0.35 to $1.00 for each strip used in home monitoring methods. Type 1 diabetics may test as often as 4 to 10 times a day. Thus, daily testing can be expensive. Manufacturers often provide meters at no cost to induce the use of the profitable test strips. For clinical laboratories, glucose determinations range from $3 to over $100 in the US and around the world. In the case of insulin analysis, prices range from $25 to $130 USD in the US and around the world. Diabetes diagnostic tests that include specific tests for measuring glucose and insulin levels can cost between $190 to $350, which is very expensive for diabetic patients.
The sensors and methods described herein address the issues of sensitivity and cost that are problems associated with current technologies available on the market.